06 julio 2014

Researchers May Have Discovered The Consciousness On/Off Switch

July 3, 2014 | by Justine Alford

Researchers from the George Washington University have managed to
switch consciousness on and off in an epileptic woman by stimulating a
single region of the brain with electrical impulses. While this is a
single case study, it provides an exciting insight into the neural
mechanisms behind consciousness, a subject of great interest that is
poorly understood despite decades of research. The study has been published in Epilepsy & Behavior.Consciousness
is a fascinating topic that has both intrigued and puzzled scientists
and philosophers for centuries. Despite significant advances in our
understanding of the brain, little is known about the neural networks
that underpin consciousness. However, research has hinted that
consciousness is likely the result of an integration of activity from
numerous different areas of the brain, marrying all of our perceptions
together into one experience. But what is the central hub to this
process?
A few years back, Francis Crick, one of the scientists involved in
deciphering the structure of DNA, and colleague Christof Koch proposed
that a brain region known as the claustrum may be at the heart of
consciousness, stringing together the constant input of information
arriving from different brain networks.
Now, in the latest study, researchers demonstrate that their
hypothesis might be correct after all. The scientists stumbled upon this
finding whilst stimulating different areas of the brain of an epileptic
woman and measuring resultant activity in order to find the epicenter
of her seizures. They discovered
that electrical stimulation with an electrode placed between the left
claustrum and anterior-dorsal insula caused the woman to lose
consciousness. She completely stopped moving, became unresponsive and
her breathing slowed.When the researchers stopped the stimulation, she regained
consciousness and couldn’t remember the event. Furthermore, the effects
were reproducible as the same outcome occurred each time they stimulated
this region over a period of two days. To make sure they were not
merely interfering with motor control or speech, they asked the woman to
repeat a particular word or perform a certain movement as the
stimulation commenced. The woman gradually spoke more quietly and moved
less and less as she became unconscious, rather than immediately
stopping, suggesting this was affecting consciousness. They also did not
identify any associated epileptic activity, suggesting it was not
merely a seizure.
Lead author Mohamad Koubeissi told New Scientist he believes that the results do suggest that the claustrum plays a pivotal role in consciousness. “I would liken it to a car,” he said.
“A car on the road has many parts that facilitate its movement- the
gas, the transmission, the engine- but there’s only one spot where you
turn the key and it all switches on and works together. So while
consciousness is a complicated process created via many structures and
networks- we may have found the key.”However, some experts have highlighted
the difficulties in interpreting findings from only 1 case study.
Furthermore, the woman was missing part of her hippocampus and therefore
is not representative of a “normal” brain. Still, it is agreed that the
study is important and certainly informative, especially since the
woman was awake in the study rather than asleep or in a coma like in
many other studies.
Koch also expressed interest in the research. “This study is
incredibly intriguing but it is one brick in a large edifice of
consciousness that we’re trying to build,” he said.
[Via New Scientist and Epilepsy & Behavior] [Header image "Working Brain" by Gontzal del Caño, via Flickr, used in accordance with CC BY-NC-SA 2.0)

Read more at http://www.iflscience.com/brain/researchers-may-have-discovered-consciousness-onoff-switch#MdWex66wZE6z9Uu4.99